This invention relates generally to the art of speaker systems designed for sound reproduction, and more specifically concerns those speaker systems which include one or more speakers characterized by the presence of front and back waves produced by a vibrating diaphragm.
A major problem of conventional speaker systems which use a vibrating diaphragm to produce sound is the adverse affect on the sound resulting from the back wave which is produced off the rear surface of the diaphragm of the speaker or speakers in the system. The vibrating diaphragm produces a front wave off its front surface, and a back wave off its back surface. If the back wave is not dealt with in some manner, it will reflect off solid objects, moving back in front of the speaker, where it mixes with the front wave, typically substantially reducing the front wave. This has a substantial negative impact on the efficiency and the fidelity of the system. In some cases, particularly at low frequencies, the speaker system will produce very little sound, because the back wave has virtually cancelled the front wave.
One solution to the back wave problem is to incorporate a speaker as part of a sealed chamber, so that the back wave produced by the speaker is captured within the chamber. However, in the operation of such a system, a varying pressure is produced within the chamber which tends to resist a change in the movement of the speaker diaphragm, thus significantly decreasing the efficiency of the speaker system or increasing system resonance. Other solutions, such as baffles, vented systems, and special horns also suffer from this disadvantageous decrease in system efficiency or lack of bass response.
Accordingly, it is an object of the present invention to provide a speaker system which deals with the back wave from diaphragm speakers in such a manner as to overcome one or more of the disadvantages of the prior art discussed above.
It is another object of the present invention to provide such a speaker system which includes an air-impermeable chamber in which the pressure and special volume of the chamber is maintained substantially constant.
It is a further object of the present invention to provide such a speaker system in which the back wave is used to improve the sound characteristics of the speaker system.
It is an additional object of the present invention to provide such a speaker system which has a substantially higher efficiency than present speaker systems.
It is yet another object of the present invention to provide such a speaker system having an improved bass response.
It is a still further object of the present invention to provide such a speaker system which can effectively use full range loudspeakers.